Ultrasonic flow meter calibration system and method

Abstract

An ultrasonic flow meter configured to measure a flow within a conduit configured for autozeroing during active flow operation of the flow meter. The flow meter includes a printed circuit board including circuitry for conducting ultrasonic transit time flow measurements, the printed circuit board including transducer swap relays and first and second transducer cables connecting the first and second transducers, respectively, to the transducer swap relays. The flow meter further includes a programmable processor configured to generate flow measurement data based on an ultrasonic flow meter calibration performed by the ultrasonic flow meter in situ while measuring flow through the conduit. Calibration includes determining a zero offset value, determining a swap offset value by measuring transit time forward and backward between the first and second transducers through the flow in the conduit, activating the transducer swap relays to physically swap the first and second transducers, and measuring transit time forward and backward between the swapped first and second transducers through the flow in the conduit, determining a flow zero value based on the zero offset and swap offset, and generating flow rate data based on the flow in the conduit and the flow zero offset.

Description

FIELD OF THE INVENTION[0001]This application relates to the field of fluid measurement devices. More specifically, this application relates to an ultrasonic flow meter calibration system and method for determining a zero-offset during active flow.BACKGROUND[0002]Ultrasonic flow meters utilize transducers to send and receive ultrasonic signals through a flow stream to measure the velocity of flow through a conduit. Where the transducers include an upstream transducer and a downstream transducer, the flow meter is configured to measure a “time-of-flight” of an ultrasonic signal transmitted between the two, spaced apart, transducers. The ultrasonic signal travels from a first transducer, along an ultrasonic signal path through the fluid and / or gas flowing through the conduit, to be received by a second transducer. The elapsed time between when the signal is sent from the first transducer and received by the second transducer is the time-of-flight. The signal may then be sent in a rever...

AI Technical Summary

Benefits of technology

The present invention provides an ultrasonic flow meter that can measure the flow of a fluid within a conduit during operation. The flow meter includes a printed circuit board with transducers and transducer cables to conduct ultrasonic flow measurements. The flow meter also includes a programmable processor that can generate flow measurement data based on an ultrasonic flow meter calibration performed during flow operation. The calibration includes determining a zero offset value and a swap offset value based on measurements taken before and after activating transducer switch relays. The processor can initiate the calibration based on user input or periodically. The invention also provides a computer-implemented method for autozeroing an ultrasonic flow meter and generating flow rate data based on the flow in the conduit and the flow zero value. The technical effect of the invention is to improve the accuracy and reliability of ultrasonic flow meters for measuring the flow of fluids in a conduit.

Problems solved by technology

No flow meter matches the theory perfectly.

Giving a large uncertainty value may reduce meter accuracy and, as such, is impractical for some application.

These factors can also drift over time, affecting the flow meter calibration.

However, it is often impractical to arrange fix there to be zero flow through the conduit being measured.

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